Radio control device



2 Sheets-Sheet l .H. Z. BENTON ETAL RADIO CONTROL DEVICE Filed Aug. 15, 1940 z/ 2752 .f1/2f 25 J5 opt. 2s, 1941.

J3 JJ Oct. 28, 1941. H.`z. BENTON ETAL 2,260,985

RADIO CONTROL DEVICE Filed Aug. 13, 1940 2 Sheets-Sheet 2 IN VENTORS Harald Z. Benlwz and Patented Oct. 28, 1941 UNITED STATES PATENT OFFICE RADIO CONTROL DEVICE of Illinois Application August 13, 1940, Serial No. 352,360

4 claims.

This invention relates to a new and improved radio control device and more particularly to a tuner of the type affording relative movementl between a coil and metallic core.

Cores have been developed which are substantially uniform in character and which comprise iron particles so ne in size as to reduce eddy current and hysteresis losses at high frequencies to such an extent that they are suitable for use at radio frequencies. These cores may be made small in size and when associated with properly designed coils have an effective permeability adequate to tune the coil over the usual broadcast range. This tuning may be accomplished by relative movement between the coil and core so as to vary the effective inductance of the coil. Since tuning in this manner is caused by a relatively short movement of the coil or core, an accurate and close adjustment is required with a mechanism free Afrom backlash or looseness.

Tuning apparatus of this character are especlally suitable for use with the compact types of radio sets which form a large part of the present commercial production of radio receivers. It is desirable to provide the tuning elements in as device for eiiicient and accurate permeability 2 tuning.

It is an additional object to provide a tuning device of this character combined with a jointly operated dial mechanism.

It is also an object to provide a tuning device substantially free from backlash and adapted for simple and easy adjustment or alignment of the tuning mechanism and the indicating mechanism. e

It is a further object to provide a construction which is composed of but few parts and adapted for commercial production and use.

Other and further objects will appear as the description proceeds.

We have shown a preferred embodiment of our invention in the accompanying drawings, in Which- Figure l is a face view of the complete unit;

Figure 2 is a view as seen from above;

Figure 3 is a rear view of the unit;

Figure 4 is a view, similar to Figure 3, showing a modified form of construction;

Figure 5 is a similar view oi' another modified form; and

Figure 6 is a similar view of an additional modi- Iication.

Referring first to Figures 1, 2 and 3, the frame II' may be formed from sheet metal and is provided with the rearwardly extending coil supporting arms I2, I3, I4 and I5. to resiliently support the coil forms I6 and Il which carry the coils I8 and I 9. respectively. The frame II, in the construction shown, is also provided with the integrally formed, rearwardly extending guide members 2U and 2|, the rear ends of which have reduced portions 22 and 23 extending through openings in a plate 24 and deformed to secure the plate in position. The members and 2| have aligned rectangular openings therein to receive the slide 25. 'I'he shaft 26 has a front bearing in the body of the plate I I between the members 20 and 2|, and has a reduced rear portion 21 bearing in the plate 24. The slide 25 is provided with an elongated slot 28 through which this reduced shaft portion 2`I` passes. The slot 28 is of such length as to permit an extended reciprocating motion of the slide 25.

l One end of slide 25 has secured thereto the crosshead 29, which has spaced threaded openings therein to receive the threaded rods 30 and 3|. These rods 30 and 3| are aligned with the axes of the coil forms I6 yand I'I and have the cores 32 and 33 secured to them, respectively. These cores are cylindrical in form and of a size to slide freely within the associated coil forms.

It will be understood that the coil forms are made from non-conducting material such as heavy paper or Bakelite or other similar material. The cores are formed from iinely divided metallic particles such as iron, heldin any suitable 4binder to form a rigid structure. The ends of rods 30 and 3|, which extend through the crosshead 29, may be slotted to permit adjustment of the rods relative to the crosshead in making and aligning adjustment of the coil and core.combinations. Similarly the coil forms I6 and I1 may be moved longitudinally in their supportingarms for such adjustment. vEither or both-adjustments may be maintained by placing wax or similar material upon the points of support or connection after the desired adjustment has been reached.

The inner end of the shaft 26 is provided with a small drum 34 which is secured to the shaft and rotates therewith. A cable 35 has a turn These arms are split extending around the drum 34 and, as shown at 36 in Figure 3, is secured to the drum at an intermediate point. One end 31 of the cable is fixedly secured to an arm 38 which is secured to the end of the slide 25 opposite to the crosshead 28. The opposite end 33 of the cable is secured to a spring 40, which spring is secured to the crosshead 29. This spring serves to maintain a uniform tension upon the cable 25 and prevents backlash or play in the movement of the slide by rotation of the shaft 23.

The upper front portion of the frame I I carries the dial bracket 4I, which is secured thereto by screws 42 and 43. As shown in Figure 2, the body of this bracket 4I is spaced from the frame II and the cable guide pins 44 and 45 extend rearwardly from the bracket. In front of the frame II the shaft 23 carries the large drum 46 about which passes the cable 41. As best shown in Figure 1, the ends 48 and 48 of the cable pass inwardly through slots 50 and 5I in the drum and are connected to a coil spring 52 which encircles the shaft 26 and maintains a uniform tension upon the cable 41. The intermediate portion of cable 41 passes around the cable guide pins 44 and 45 and is connected tothe indicator slide 53 which has the downwardly extending indicator arm 54 passing in front of a dial scale 55 which is secured to the face of the dial bracket 4I.

The assembly of the device will be obvious from the description and showing in the drawings. The

indicator 54 will be driven by rotation of shaft 26 at the same time that the cores 32 and 33 are moved axially in and out relative to the coils I8 and I9 on the coil forms I8 and. I1. The cores and their associated coils are properly aligned so that the circuits which they control, such as the antenna circuit and oscillator circuit of a superheterodyne receiver, are tuned to the desired different frequencies and the parts are so proportioned that the tuned circuits are maintained in substantially the Same relationship throughout the limits of movement of the tuning apparatus. The dial indicator slide may be acljusted relative to its drive cable 41 so as to properly indicate the kilocycles or wave length to which the circuits are tuned.

The form of construction shown in Figure 4 is similar to the construction of Figures 1 to 3 with the exception of the location and connection of the core and dial drive means. The frame 60 supports the coils BI and 62 and the slide 83 which serves to move the cores 84 and 65. The dial indicator slide 63 is carried adjacent the edge of the frame 80 in the same manner as in the construction of Figure 1. Instead of a drive shaft such as shown in Figures 1 to 3, the conl struction of Figure 4 is shown as provided with a shaft 61 which carries the core drive drum B8 and the dial drive drum 69, the shaft being supported independently of the frame B0. It will be understood that' shaft 61 may be supported anywhere desired upon the radio set chassis, panel or housing. The core slide 83 is driven by cable 10 passing around drum 3l and about guide pins 1I and 12 on the frame 80. The dial indicator 66 is driven by cable 13 passing around drum 69 and guide pins 14 and 1i on the frame.

The construction shown in Figure comprises the frame 80, supporting the coils 8| and 82, in which the cores 83 and 34 are moved by slide l5 guided in the arms 86 and 81 extending rearwardly from frame 30. The frame 80 carries the rotatable shaft 88 in the arms 36 and 31 and this aaedoss shaft is also guided -by an arm 39 located at the left edge of the frame 80, as seen in Figure 5. The slide 85 is moved by cable 90 which passes about guide .pins 9| and 92 and has several turns around the shaft 38. The construction is suitable for use where it is desired to have the frame and assembly extend from front to back of the chassis, the shaft 33 extending beyond the front of the chassis. The frame may extend vertically or horizontally as desired.

The form of construction of Figure 6 uses the same frame 80 as shown in Figure 5, but is provided with a shaft 95 extending normal to the frame adjacent one edge thereof instead cf a shaft 88 as in Figure 5, extending parallel to the frame. `The shaft 85 is supported in the frame 80 and in a bracket 96 and is provided with a cable drum 91. Cable 98 passes about drum 31 and guide pin 33 to drive the slide |00. This construction is suitable for use Where it is desired to have the tuning knob closely adjacent an edge of the panel or housing for the set to be tuned.

It Will be understood that the diierent forms of tuning apparatus shown are adapted for use with various radio circuits and that one or more core and coil combinations may be tuned by means of any of the mechanism shown, depending upon the circuit in use. The apparatus is compact and may be mounted as a unit upon a receiving set chassis, and constitutes the radio frequency portion of the assembled radio set. It takes up a small space on any desired portion of the chassis and the coils may be connected'to their associated elements of the circuit by short connecting wires.

If desired, the frame and other parts may be formed of non-magnetic material, such as brass, so as to minimize the effect on the coils. The arms supporting the coils may be of a suitable length to space the coils adequately from the other metal parts of the assembly. The apparatus may jointly and simultaneously drive the dial mechanism and the tuning mechanism, and

means are provided for preventing backlash be` tween the drive shaft and both the dial and the tuning mechanism, so that they will be maintained in alignment accurately during the operation of the device. The forms of construction of Figures 5 and 6 may also have dial mechanism directly associated with them.

While certain preferred forms of construction have been shown, it is capable of further change or variation to meet differing conditions and requirements and we contemplate such modifications as come within the spirit and scope of the appended claims. While the invention is disclosed in conjunction with permeability tuning, it will be clear from the foregoing that it is equally suitable to other forms of tuning, particularly such as coaxial capacity tuning.

What is claimed is:

1. In apparatus for radio tuning purposes, the combination of a frame, spaced supports on said frame, a reciprocating slide guided through said spaced supports, a control shaft journalled in said spaced supports substantially parallel with said slide, cable connections from said shaft to the opposite ends of said slide for effecting reciprocation of said slide in opposite directions and a screw having adjustable screw engagement with said slide, said screw extending from said point of adjustable engagement with said slide substan- 2. In apparatus of the character disclosed, a frame, spaced guide members projecting rearwardly therefrom and having aligned rectangular openings therethrough, a flat slide guided through said openings, angularly projecting cross heads at the opposite ends of said slide, a control shaft, a bowed flat spring on one of the cross heads, a cable having one end connected to said bowed fiat spring and having its intermediate portion operatively connected with said shaft and its opposite end connected with the other cross head and screw connecting means extending through one of said cross heads toward the opposite cross head for eiiecting operation of a tuning element or the like.

3. In apparatus of the character disclosed, a frame, spaced guide members projecting` rearwardly therefrom and having aligned rectangular openings therethrough, a flat slide guided through said openings, angularly projecting cross "heads at the opposite ends of said slide, a control shaft, a bowed flat spring on one of the cross heads, a cable having one end connected to said bowed nat spring and having its intermediate por tion operatively connected with said shaft and its opposite end connected with the other cross head and screw connecting means extending through one of said cross heads toward the opposite cross head for eiecting operation of a tuning element or the like, said shaft extending rearwardly of the frame between said rearwardly projecting guide members, a plate connecting the rearward ends of said guide members. said shaft having a journal mounting in said frame and plate.

4. In apparatus of the character disclosed, a frame, spaced guide members projecting rearwardly therefrom and having aligned rectangular openings therethrough, a iiat slide guided through said openings, angularly projecting cross heads at the opposite ends of said slide, a con trol shaft, a bowed flat spring on one of the cross heads, a cable having one end connected to said bowed flat spring and having its intermediate portion operatively connected with said shaft and its opposite end connected with the other cross head, screw connecting means extending through one of said cross heads toward the opposite cross head for effecting operation of a tuning element or the like, a reciprocating indicator slidably guided on the frame, a cable having its intermediate portion connected with said indicator and a coiled spring connecting opposite ends of said cable about the shaft.

HAROLD Z. BENTGN. LLOYD P. MGRRXS. 

